I'm trying to boot into Ubuntu but the problem is that the boot manager menu is not showing me the USB boot option. It says that the system doesn't have any USB boot optiion. How to fix this issue. N.B: I used Rufus to create a bootable flash drive and installed the LTS version of Ubuntu/ My pc brand is Lenovo --> IdeaPad 3 15iau7 so you can say it's a modern laptop/I disabled the secure boot option and still the same problem.
I figured out the solution to this problem(finally) : First, you need to check wether the USB drive is corrupted,if so you need to buy a new one.Second, disable secure boot under the security section as well as Fast boot under the boot section .Finally, turn off the bitlocker encryption .If you are using the Home version of windows 11,you then need to disable it using powershell.Don't forget to run it as administrator.And you should be free to go.
If you still encounter the same issue, trying out different ports would likely solve it.
I assume that you had the bootable USB drive inserted and tried to enter the boot menue by hitting F11 or the delete key repeatedly during the boot process. If that was the case try another USB port. If that doesn't help I would assume that the USB drive isn't really bootable. Download your Ubuntu iso and use Ubuntu start disk creator to make a new one.